Hydropower or hydroelectricity is an established renewable energy technology that also may be quite low-cost. Although hydropower requires a steep infrastructure investment to develop, dams in particular have a long lifespan and generally can produce consistent power over many decades. Consider that the Hoover Dam in the US Southwest has been in service since 1935 and still produces over 4.5 billion kilowatt hours per year.

Hydroelectric power includes massive hydroelectric dams like the Hoover, but also small run-of-the-river plants. Large dams continue to be built in many parts of the world, like China (Three Gorges) and Brazil (Belo Monte). As those linked articles make clear, hydropower is not without its shortcomings– the high initial cost of development can strain national finances and the human displacement and environmental impact from diverting and blocking rivers can be severe.

This cost report on Hydroelectricity from the International Renewable Energy limits itself to the data and metrics based on up-to-date and reliable information which can be used to understand the costs and performance of hydroelectric power. For climate change mitigation, hydropower is seen as a key tool – as this report notes, the Intergovernmental Panel on Climate Change (IPCC) expects (and is counting on) a median increase in the amount of hydropower generation of 35 % by 2030 and 59 % by 2050.